Manual Changes - HP 400D Operating And Servicing Manual

MANUAL CHANGES

ERRATA:
Sect. 11 Page 4-Subparagraph
Delete all of the information to the end of the section .
Replace with the following:
AMPLIFIER
C.
With full scale meter deflection,
output is approximately
/ /
Model 400D H
signals less than approximately
be obtained with the RANGE switch on the
Be careful not to overdrive the amplifier.
a range which gives
nals more than about
tortion. The impedance
approximately
The frequency response and voltage calibration of the instru­
ment may be affected by any external load impedance applied
to the output terminals.
edges of the
You can quickly check the effect of the
Observe the meter reading obtained with the output terminals
open circuited a nd then note
external circuit is connected to the OUTPUT terminals.
this shift is negligible,
fected appreciably by the load.
put signal is changed;
of frequencies is applied,
above
0
ADDENDUM:
For instruments with Serials Prefixed:
Model 400D, Serial
and above; Model 400L,
corrections listed aboveo
12/15/59
MODEL 400D
VACUUM TUBE VOLTMETER
"C"9
Ou15
L thus is useful as an amplifier with input
meter deflection near full scale.
a
2
times full scale will cause severe dis­
looking into the
50
ohms.
The effect will be greater near the
nominal band pass of the amplifier.
the measurement is not being af­
ioe.,
repeat the quick check described
and above;
Serial
1/6/60
/ /
H L
Amplifier:
the amplifier open circuit
volts rms on any range.
0.1
volt. Maximum gain will
0.001
You should select
O
UTPUT terminals is
applied load:
any shift of reading when the
When the nature of the in­
a different frequency or band
400H,
Model
6516
and above applies with all
The
volt position.
Sig­
If
the manual for
6526
Serial